1. Field of the Invention
The present invention relates to an image generating device, an endoscope system, and an image generating method capable of simultaneously obtaining a normal image, which is a color image of an object illuminated with white light, and a spectral image, which is an image generated using a specific color component. The positional relation of the normal image and the spectral image is such that the images are of an identical object.
2. Description of the Related Art
In recent years, a capsule-shaped body-insertable apparatus (e.g., a capsule endoscope) equipped with an imaging function and a wireless communication function has been proposed, and a body-insertable apparatus system for capturing images of the inside of a subject by using the capsule endoscope has been developed. In order to enable observation (examination) of the inside of a subject, the capsule endoscope functions, from when it is swallowed from a mouth of the subject to when it is naturally excreted from the subject, such that it moves inside a body cavity, e.g., inside organs such as a stomach and a small intestine, by peristalsis and the like and captures images of the inside of the subject at, e.g., 0.5-second intervals.
While the capsule endoscope travels inside the subject, an external image display device receives images captured by the capsule endoscope via an antenna arranged on the body surface of the subject. The image display device has a wireless communication function for the capsule endoscope and a memory function for the images, and sequentially stores the images received from the capsule endoscope inside the subject in a memory. Doctors and nurses display the images accumulated in the image display device, i.e., the images of the inside of the digestive tract of the subject, on a display, so that they can observe (examine) the inside of the subject to make a diagnosis.
Japanese Laid-open Patent Publication No. 2006-297093 discloses a technology for applying a color filter array (CFA) in which the percentage of blue sensing elements is increased compared to those of red sensing elements and green sensing elements in order to obtain sharp images when in-vivo images are acquired. This technology is based on the fact that blue light has a shorter wavelength than other light and is reflected by the surface of a body tissue without reaching the inside of the body tissue to be scattered.